Subjective memory complaints, depressive symptoms and cognition in Parkinson's disease patients

Background and purpose The goal of this study was to establish the prevalence of subjective memory complaints ( SMC s) and depressive symptoms ( DS )s and their relation to cognitive functioning in patients with Parkinson's disease ( PD ). Methods In all, 248 controls and 104 PD patients were included in the study. The PD group was subdivided into three PD subtypes with mild cognitive impairment ( MCI ) according to the Petersen criteria and three PD subtypes with MCI according to the Litvan criteria. Results Substantial SMC s were reported by 7.7% of controls and 16.3% of the PD patients ( P  < 0.001). A clinically relevant degree of DS s was evident in 16.6% of controls compared with 40.4% in the PD group ( P  < 0.001). An analysis of variance revealed a statistically significant difference for SMC s across all Petersen groups as well across all Litvan groups. Two‐factor analyses of variance with the factors cognitive status ( MCI subtype) and depressive state (depressed versus not depressed) and SMC s as dependent variable revealed significant results. Conclusions Approximately 15% of PD patients seeking help in a movement disorder clinic report significant SMC s, with an increasing degree from cognitively healthy PD to PD ‐ MCI . Significant DSs increase SMC s across all cognitive status groups.